Exchange 2010: ExchangeGuid is mandatory on UserMailbox

Issue:
A lot of companies use some kind of script to "create" a Microsoft Exchange 2003 mailbox. Usually this is done by setting the following attributes on the user account in Active Directory:

• msExchHomeServerName
• homeMDB
• homeMTA
• mDBUseDefaults
• mailnickname
• proxyAddresses

 

When moving over to Microsoft Exchange 2010, the companies change the "msExchHomeServerName", "homeMDB" and "homeMTA" to the new Microsoft Exchange 2010 server.

 

When looking in the Microsoft Exchange Management Console, the mailbox appears as a "Legacy Mailbox"

 

 

This can be solved by setting some extra attributes on the user in Active Directory:

• msExchRecipientTypeDetails
• msExchRecipientDisplayType
• msExchVersion 

It looks like the mailbox has been created correctly. The mailbox can be accessed and managed.

Now the MS Exchange 2003 server is turned off. The script still creates a mailbox and everything looks ok. Only when you the properties of a newly created mailbox, the following message appears:

 After clicking "OK" and clicking "Apply" to save the changes the message below appears:

 

 

 

 

 

 

 

 

 

 

 

No matter what you do, you cannot get rid of this message.

 

 

Cause:

Microsoft Exchange 2003 has the RUS (Recipient Update Service) which add missing attributes to an account in Active Directory. Since the Microsoft Exchange 2003 server is turned off, RUS is not running anymore and will not update the missing Active Directory attributes.

 

 

Solution:

The only solution I have found is to create the mailboxes the proper way: Using PowerShell.